This disclosure relates to methods for displaying and analyzing statistical data retrieved from Small Computer Systems Interface magnetic tapes.
The term xe2x80x9cSCSI Enhanced Tapexe2x80x9d signifies the family of SCSI half-inch cartridge tape subsystems adhering to the ANSI SCSI-2 Standard. ANSI refers to the American National Standards Institute. Each SCSI Enhanced Tape drive uses a form of half-inch cartridge media. The 36-Track subsystems use a 3890 and/or 3890 Extended tape.
The 36-Track tape subsystems were introduced in 1993 by vendors such as IBM, Fujitsu, and StorageTek, as an increased capacity replacement for 18-Track tape subsystems. These 36-Track tape subsystems provide the ability to store twice the capacity of a regular 18-Track using the same media, and up to two times the capacity using a new, extended half-inch tape cartridge, assuming that both subsystems utilize data compression.
The SCSI 36-Track tapes involved herein are Unisys tape systems designated as the OST5136, the CTS5236, and the CLU9710-36T tape subsystems. The density requirements directly correlate to the FIPS (Federal Information Processing Standard) CTS5136 subsystems, in that they can read at the 18-Track density, and then either Read or Write at the 36-Track density. The SCSI 36-Track tapes are considered to be compatible with their FIPS counterparts. They are expected to read media written by the FIPS 36-Track or 18-Track subsystems and these FIPS subsystems are considered to be able to read media written by any of the SCSI 36-Track subsystems.
Other tapes involved in the present system are the CLU9710-DLT4 and the CLU9710-DLT7 tapes which were introduced by the Quantum Corporation as a high-performance, high-capacity streaming cartridge tape product. The CLU9710-DLT4 subsystem provides a formatted capacity of up to 40.0 GB on a DLTIV tape and sustained user data transfer rates of 10.0 megabytes per second assuming compression is being utilized. The CLU9710-DLT7 can provide 70.0 GB capacity under the same circumstances.
These enhanced type SCSI subsystems are being supported via newer Unisys A-Series and NX I/O platforms, for example, those designated as RMM/IOM platforms, and are currently only connected via a Native SCSI channel.
A number of functionalities are being provided in connection with these tape subsystems of which the present focus is that involving statistical data analysis and reporting after statistical data collection is performed as has been seen in co-pending U.S. Ser. No. 09/209,985 now U.S. Pat. No. 6,269,422B1, entitled xe2x80x9cSystem and Method for Retrieving Tape Statistical Dataxe2x80x9d which is incorporated herein by reference.
Statistical data gathering of a magnetic tape involves identifying various pages supported by the magnetic tape and then selecting certain data to indicate counts of such things as (i) Write errors; (ii) Read errors; (iii) Sequential-Access device pages; (iv) Track errors.
The earlier methods for gathering statistical data for a tape subsystem (such as the USR 5073) involved tagging an Unload command, and then upon completion of the Unload, issuing a single Log Sense I/O command to retrieve all the available statistical data for the drive. These internally stored statistics are xe2x80x9cclearedxe2x80x9d as a result of a Log Select I/O command. The problem with this method is two fold; 1) SCSI Enhanced Tape drives do not necessarily support a page code designated xe2x80x9cReturn All Supported Pagesxe2x80x9d - - - which would not allow all the statistics to be retrieved with a single I/O; and 2) the tape drive""s internally stored statistical data is cleared as a direct result of an xe2x80x9cUnloadxe2x80x9d which would result in xe2x80x9cjust-clearedxe2x80x9d statistics being retrieved with the pre-existing algorithm. Thus, this prior algorithmic method was never sufficient to gather the required statistical data for SCSI Enhanced Tapes.
One of the SCSI Enhanced tape drives, designated the xe2x80x9cOST5136,xe2x80x9d does support a xe2x80x9cReturn All Supported Pagesxe2x80x9d page. However, the volume amount of information it returns is prohibitive since it requires a huge buffer dimension. Here, the buffer required would be significantly larger than the standard buffer required to piece together the data returned for each page, when each page is requested individually.
The above-referenced co-pending companion case entitled xe2x80x9cSystem and Method for Retrieving Tape Statistical Dataxe2x80x9d, U.S. Ser. No. 09/209,985, now U.S. Pat. No. 6,269,422B1, described a method for unloading magnetic tape media from a magnetic tape drive and preserving the statistics data by allowing the statistics data to be read-out and placed in a Sumlog file.
After the completion of the retrieval of the statistical data into the Sumlog file, it is then necessary to read-out and analyze this data and place it in a format that is suitable for a field engineer to understand and to particularize any area of problem or trouble that may be occurring in the particular tape drive and its tape media. This present application now indicates how the retrieved statistical data can now be read-out and displayed and then made available for analysis by a User or field engineer in order to verify the integrity of the data in addition to pinpointing any trouble or problem areas which may be occurring. The information now provides relevant information in a specially formatted and legible manner, rather than just a dump of data which would be difficult to analyze.
This invention involves the read-out and analysis of statistical data retrieved from a magnetic tape unit. Statistical data is retrieved from the Unload operation on a magnetic tape unit after which it is deposited into a recording medium designated as a Sumlog file.
Once the statistical data has been retrieved and recorded, it is now necessary to programmatically read-out and display this data via a printer or an Operator Display Terminal and have it be presented in a particular format under which a User or field engineer will be able to garner information on various pages of the read-out data. Thus, the read-out format will indicate a particular page and indicate the Write errors in it, in addition to showing the Write errors which have been corrected by an error correction code. Additionally, another page read-out may show the Read errors which came from the magnetic tape media. Then there may be a page format which shows the track error statistics which indicate specifically, each of the individual tracks, of which there may be up to 18 tracks, and the errors which occurred on each one of the particular recording tracks involved.
The statistical data from the Sumlog file is fed to a Loganalyzer program which is then connected to a Jobformatter Library which arranges the data for display to a printer or to an Operator Display Terminal.
A keyboard is used to initiate a specialized command xe2x80x9cLOG MAINT MT DUMPEXTRDxe2x80x9d which invokes the Loganalyzer program, requesting this program to analyze the I/O error Sumlog entries with a special analysis. Then, the Jobformatter Library will become involved via a procedure designated xe2x80x9cDUMP_LOGSENSE_DATAxe2x80x9d which will parse through data from certain pages which are designated as supported pages. Then, Jobformatter will arrange to print-out or display a readable, understandable, statistical data analysis to be output to a terminal or printer.
Once the data has been formatted according to each one of the supported pages and displayed, it is then in a condition to be looked-at and analyzed by a User or field engineer in order to diagnose any type of problems which may have been occurring.